The present invention relates in general to sub-sea oil well equipment and in particular to means for providing a flexible supportive joint between buoyancy chambers of flotation means provided for a sub-sea riser conduit run from a floating vessel to a sub-sea well.
Flotation means for sub-sea well risers have been developed heretofore and in particular as disclosed in prior U.S. Pat. No. 3,858,401. In that patent, a plurality of buoyancy chambers are mounted about a plurality of riser conduits run from a floating vessel to a well. Gas conduits connected each chamber with a source of compressed gas on the floating vessel in order that selectable amounts of buoyancy could be introduced into the riser system. The various advantages of being able to disconnect from the riser conduit, leaving it floating in the sea, and providing support for the long conduits during drilling operations where vessel movement may occur were explained in that patent. Even with the improvement of the flotation means of U.S. Pat. No. 3,858,401, there will still be some bending and/or flexing of the riser conduit due to movement of the vessel on the surface of the sea. It is therefore desirable to provide the flotation means for such sub-sea risers in such a manner as to not reduce the flexibility or bendability of the riser conduit.
It is therefore the primary object of the present invention to disclose and provide an improved manner of mounting flotation means to a sub-sea well riser conduit such that the mounting of the associated buoyancy chambers does not unduly increase stress on the riser, unduly increase its rigidity or unduly limit its flexibility under normal conditions of use as can be expected in deep off-shore sub-sea well drilling operations.
It is a still further object of the present invention to disclose and provide an improvement in flotation means for a sub-sea well riser to provide a flexible supportive joint for use between each buoyancy chamber and each associated riser conduit whereby the chambers may flex relative to the riser conduit and thus not impair its overall flexibility as normally required in deep off-shore drilling operations.
It is a still further object of the present invention to disclose and provide an improvement in flexible supportive joint for buoyancy chambers associated with a riser wherein an elastomeric member may be provided in a supporting relation between the chambers and riser conduits as well as providing for a flexible interconnection.
It is a still further object of the present invention to disclose and provide mechanical flexible joint means suitable for use between flotation means buoyancy chambers and an associated riser conduit section alone and in connection with flexible supportive elastomeric joint members.
These and other objects of the present invention will become more readily apparent to those skilled in the art from a consideration of the detailed description of preferred and alternative exemplary embodiments thereof set forth hereinafter.